拟南芥PP2C35/74与SnRK2.2相互作用调控ABA信号通路的作用机理研究

ABA信号通路的核心组分SnRK2s激酶活性受蛋白质的可逆磷酸化调节。蛋白磷酸酶PP2C A亚家族和TOPP1通过脱磷酸化SnRK2s在ABA信号通路中发挥负调控作用，而发挥正调控作用的蛋白磷酸酶报道较少。我们前期研究发现PP2C家族蛋白磷酸酶PP2C35及其同源基因PP2C74可能正调控ABA信号通路，并且这两个蛋白能够与SnRK2.2直接互作且其互作在ABA处理后增强，同时PP2C35能影响SnRK2.2下游蛋白ABI5的积累。本项目中，我们拟开展（1）PP2C35/74在调节植物ABA响应中的作用；（2）ABA对PP2C35/74的调控方式的研究；（3）PP2C35/74与SnRK2s相互作用机理的研究来解析PP2C35/74调节ABA信号通路的分子机制。本项目不仅为全面了解蛋白磷酸酶在ABA信号通路中的作用提供新的线索，并为ABA信号通路中SnRK2s的活性调节方式提供新的机制。

As the core component of ABA signal pathway, protein kinases SnRK2s are tightly controlled by reversible protein phosphorylation modification. Protein phosphatases PP2C A clade and TOPP1 interact and dephosphorylate SnRK2s to play negative role in ABA pathway, however the positive protein phosphatases in ABA pathway are less reported. Our preliminary study showed PP2C35 and its homologue PP2C74 are positive regulators in ABA signaling pathway; both PP2C35 and PP2C74 interacted with SnRK2s in vitro and in vivo, and the interaction was enhanced by ABA treatment；PP2C35 expression level affected SnRK2.2 downstream substrate ABI5’s protein accumulation. In this proposed study，we will study (1) the functional study of PP2C35/74 in ABA pathway;(2) the regulation mechanism of PP2C35/74 by ABA ;(3) the role of the interaction between PP2C35/74 and SnRK2s in regulating ABA pathway in Arabidopsis. This work will not only provide a novel mechanism that regulating SnRK2s activity but also shed new insight into ABA signal transduction mechanism.